This invention relates in general to deep fat fryers and specifically to arrangements for precluding temperature induced failures of the end welded junctions of the fry pot and burner tubes in such fryers. Deep fat fryers include a fry pot having one or more burner tubes that are secured in corresponding flared openings in opposed first and second walls therein, by edge welding their ends. The fry pot and burner tube are fabricated from stainless steel. The edge welding of the burner tubes and fry pot walls are herein referred to as end welds
In high heat or rapid recovery type deep fat fryers, the burner flame is intense. Under some conditions of use, the end welds on the burner tubes may reach very high temperatures, occasionally producing excessive stresses in the end welds that result in weld failure. One reason for the very high temperature rise is that the end welds are not fully exposed to the cooling effect of the cooking oil in the fry pot.
In U.S. Pat. No. 5,778,871, assigned to Keating of Chicago, Inc., front and rear heat shields are used to deflect heat away from the burner tube end welds. The front heat shield consists of a pair of welded, opposed flat stainless steel plates having outwardly flared openings in alignment with the front edges of the burner tubes. The smaller of the flared openings extends into the inlet of the burner end tube and shields the end weld from the burner flame. The edge of the opting does not contact the burner tube, however, and the circumferential gap between the edge of the opening and the burner tube enables air to flow over the end weld, thus contributing a cooling effect. The larger flanged opening abuts the flame-generating burner. The rear heat shield comprises another stainless steel plate that supports stainless steel tubes with lips or flared brims positioned in the outlets of the burner tubes, with suitable insulating material being placed between the burner tubes and the flared brim. This patented arrangement is partially illustrated in FIG. 3.
While satisfactorily protecting the end welds, the described patented solution is relatively costly to implement and undesirably shields a portion of the gas jets in the burner face, creating thermal inefficiencies. With the novel heat shields disclosed in the present invention, the end welds are protected in a much less costly manner and the gas burner face is unobstructed.
A principal object of the invention is to provide an improved deep fat fryer.
Another object of the invention is to provide a deep fat fryer that is less costly to manufacture.
A further object of the invention is to provide a deep fat fryer of improved reliability and efficiency.
A feature of the invention is the provision of improved front and rear heat shields for deep fat fryer burner tube end welds.